21112

Appears in sequences

• a(n) = floor( n*(n-1)*(n-2)*(n-3)/27 ).at n=29A011937
• Expansion of x/(1 - 7*x - 3*x^2).at n=6A015559
• "DHK" (bracelet, identity, unlabeled) transform of 1,3,5,7,...at n=12A032255
• Cubeful (i.e., not cubefree) palindromes.at n=32A035133
• Base-10 palindromes that start with 2.at n=33A043037
• Palindromic and divisible by 4.at n=46A045639
• Palindromic and divisible by 8.at n=23A045643
• Largest palindromic substring in 6^n.at n=48A046264
• Palindromes with exactly 6 prime factors (counted with multiplicity).at n=4A046332
• Composite palindromes whose sum of prime factors is palindromic (counted with multiplicity).at n=32A046354
• Palindromic untouchable numbers.at n=23A048187
• Positive numbers n such that n is a multiple of (product of digits of n) * (sum of digits of n).at n=15A049102
• a(n) = smallest palindrome > a(n-1) such that a(1)*a(2)*...*a(n) + 1 is prime with a(1) = 2.at n=24A051896
• Number of conics which pass through 3 points and are bitangent to a general curve of order n.at n=14A060783
• Multiples of 7 whose sum of digits is equal to 7.at n=33A063416
• Numbers m that minimize | k /(k- EulerPhi(k)) - golden ratio phi | when k runs over all the numbers with the same number of digits as m.at n=11A065758
• a(n) = (1)*(2 + 3 + 4 + ... + n) + (1 + 2)*(3 + 4 + 5 + ... + n) + (1 + 2 + 3)*(4 + 5 + 6 + ... + n) + ... + (1 + 2 + 3 + ... + n-1)*n.at n=13A067056
• Largest multiple of n using only nonzero digits with digit sum n, or 0 if no such multiple exists.at n=6A075399
• Array in which the n-th row contains the multiples of n using nonzero digits and having a digit sum of n. Sequence contains the rows and a zero entry for rows with no terms (e.g. 10).at n=28A077755
• Largest multiple of n as a concatenation of its partitions.at n=6A079840